BSODs when I play certain games

For the last couple of weeks I've been getting BSODs whenever I run some games on my computer. I have Windows 7.

The first BSODs were because of heat, so naturally I cleaned everything carefully, RAM included (I made sure it was seated correctly as well). I had also OC'd my processor, so I made sure to return it to stock speeds, which still didn't help.

However, after returning to the games after this the PC BSODs again. I wonder if it's a sound issue, because when it crashes I hear the sound go on like a "bzzzzzzzz" noise, though that could be it crashing.

Uploading files in a rar, can't attach as it's 204KB, just over the limit. =/